#include<unistd.h>
#include<stdio.h>
#include <sys/types.h>
#include<stdlib.h>
int main()
{
    pid_t pid;
    printf("Before: pid is %d\n", getpid());
    if((pid=fork())==-1){
        perror("fork()");
        exit(1);
    }
    printf("After:pid is %d, fork return %d\n",getpid(),pid);
    sleep(1);
    return 0;
}

